Rachel Weisz is set to co-star with Colin Firth in 'The Railway Man'.

The 'Deep Blue Sea' star is in final negotiations to take on the role of Patricia 'Patti' Wallace, the second wife of Colin's character Eric Lomax, a second lieutenant in the Royal Corp of Signals who is captured by the Japanese army in Singapore during World War II.

Eric is sent to a POW camp in Kanchanaburi, Thailand, where he joins thousands of other prisoners and forced to work on the infamous Burma to Siam 'death railway' and the bridge over the river Kwai.

The real life story is based on former army officer Eric's book which details his experiences as a prisoner of war, and how he set out decades later to track down his tormentors and exact some revenge. Patti was responsible for helping him to confront his fears and she also wrote to the man Eric held responsible for his torture.

'War Horse' star Jeremy Irvine will play a younger version of Colin's character during his time in captivity.

Jeremy told the Daily Mail newspaper: "Lomax suffered cruel and horrible treatment. I've been studying what happened to him and it was grim."

Jonathan Teplitzky is directing the film, with Frank Cottrell Bryce and Andy Paterson writing The Script.

Teplitzky previously said in a statement: "'The Railway Man' is an amazing story and to have the chance to make it with Colin Firth as Eric is really the best gift any director could hope for."